Takebe Katsuki, Suzuki Mamoru, Hara Yumiko, Katsutani Takuya, Motoyoshi Naomi, Itagaki Tadashi, Miyakawa Shuhei, Okamoto Kuniaki, Fukuzawa Kaori, Kobayashi Hiroko
Department of Dental Pharmacology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan.
Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
ACS Bio Med Chem Au. 2024 Sep 20;4(5):257-267. doi: 10.1021/acsbiomedchemau.4c00046. eCollection 2024 Oct 16.
The ribonuclease T1 family, including RNase Po1 secreted by , exhibits antitumor activity. Here, we resolved the Po1/guanosine-3'-monophosphate complex (3'GMP) structure at 1.75 Å. Structure comparison and fragment molecular orbital (FMO) calculation between the apo form and the Po1/3'GMP complex identified Phe38, Phe40, and Glu42 as the key binding residues. Two types of the RNase/3'GMP complex in RNasePo1 and RNase T1 were homologous to Po1, and FMO calculations elucidated that the biprotonated histidine on the β3 sheet (His36) on the β3 sheet and deprotonated Glu54 on the β4 sheet were advantageous to RNase activity. Moreover, tyrosine (Tyr34) on the β3 sheet was elucidated as a crucial catalytic residues. Mutation of Tyr34 with phenylalanine decreased RNase activity and diminished antitumor efficacy compared to that in the wild type. This suggests the importance of RNase activity in antitumor mechanisms.
核糖核酸酶T1家族，包括由……分泌的核糖核酸酶Po1，具有抗肿瘤活性。在此，我们解析了Po1/鸟苷-3'-单磷酸复合物（3'GMP）在1.75 Å分辨率下的结构。对无配体形式与Po1/3'GMP复合物进行结构比较和片段分子轨道（FMO）计算，确定苯丙氨酸38、苯丙氨酸40和谷氨酸42为关键结合残基。核糖核酸酶Po1和核糖核酸酶T1中的两种核糖核酸酶/3'GMP复合物与Po1同源，FMO计算表明，β3片层上的双质子化组氨酸（His36）和β4片层上的去质子化谷氨酸54有利于核糖核酸酶活性。此外，β3片层上的酪氨酸（Tyr34）被确定为关键催化残基。与野生型相比，用苯丙氨酸取代酪氨酸34会降低核糖核酸酶活性并减弱抗肿瘤功效。这表明核糖核酸酶活性在抗肿瘤机制中的重要性。
